This invention relates to laser glass compositions for use in high energy applications, especially high peak power applications. More particularly, this invention relates to laser glass compositions of phosphorous pentoxide which include substantial amounts of selected alkaline earth oxides, substantial amounts of selected alkali metal oxides and further include the oxides of selected earth and/or rare earth metals, and mixtures thereof. High efficiency or gain, low n.sub.2, good chemical durability and good optical quality for high energy applications are obtainable with the glasses of this invention.
It is highly desirable in the field of high peak power lasers that the laser material be efficient from the standpoint of power output compared to power input. Furthermore, the laser glass should be capable of resisting discoloration or solarization.
Glass laser compositions based on silica systems are currently used in the industry because of inherent advantages therein. More recently, some advances have been made with glass laser compositions based on phosphate systems, such as shown in U.S. Pat. no. 3,580,859, to overcome inherent disadvantages of silica systems, resulting from the structure of the silicates, their technical peculiarities and the purity of raw materials. The advances in the art with respect to phosphate systems have been limited, however, and are not used in the industry today, because these systems have, until the present invention, suffered from a number of disadvantages, including the difficulty of melting these glasses, poor optical quality and poor chemical durability. Laser phosphate glass compositions, however, generally demonstrate high gain and low n.sub.2, thereby making them attractive to further pursue improved systems for use in the industry. High gain is generally accepted as the amplification capability of a matrix, for example glass. n.sub.2 is the nonlinear refractive index coefficient, which describes the change in n. The importance of the nonlinear index, n.sub.2, in lasers stems from the fact that undesirable higher values of n.sub.2 are associated with self-focusing and frequency broadening in laser rods. Self-focusing occurs when the beam of light squeezes down upon itself to cause beam divergence and bubble formation, which leads to tracking damage.
The laser glass compositions of this invention, however, exhibit a superior balance between high gain and low n.sub.2, and possess good melting capabilities, good chemical durability and good optical quality.
Consequently, it is an object of this invention to provide a laser phosphate glass for use in high energy applications, especially high peak power applications.
It is another object of this invention to provide a laser phosphate glass which provides and balances the properties of high gain, low n.sub.2, ease of melting, good chemical durability, and good optical quality.
These and other objects will be readily apparent from the following detailed description which is intended only to illustrate and disclose the invention.